Automatic firearm



R. voN FROMMER May 3,'1930.

AUTOMATIC FIREARM Filed Aug. 18 1926 v 2 Sheets-Sheet 1 will Frommer.-

lallll l... v||| I I II I h May 13, 1930. R. voN FROMMER AUTOMATIC FIREARM 2 Sheets-Sheet 2 Filed Aug. 18 1926 l/on fram 711er Patentedv May 13, 1930 PATENT OFFICE RUDOLF voul FRQMMER, oF BUDAPEST, HUNGARY AUTOMATIC FIREARM Application filed August 18, 1926. Serial N'o. 130,082.

This invention relates t'o'automatic iirearms having an air cooled barrel sliding on a long way in the chamber of which the shell is loosened by -a shock produced by a spring buffer -against which the barrel strikes' at about the end'of its backward movement. In such guns, firing a few hundred shots a minute, a necessary condition is the possibility of a quick and easy barrel changing under all circumstances (as for example at dusk).

The present invention has for its object to provide an automatic rearm of the type above referred to, the barrel of which can be changed in a few seconds even under the most unfavorable conditions. For this purpose all vthe parts of the weapon which would influence this quick changing are so arranged as to be easily removable from the path of the barrel.

Thus for instance the striking surface of the movable. barrel is arranged yon the rear end of the same, i. e. on the rear end of a barrel extension. It is essential that this striking surface shall be arranged on a part of the barrel or the barrel extension which lies on the rear portion of the Weapon-mechanism as by this arrangement no passageways in the interior of the mechanism are necessary -for the -striking surface. Onthe other hand by the simple removal of the terminating cap of the weapon the wayfor pulling out the barrel to be changed is made free, so that no obstruction opposes the free pasn sage of the striking surface and thus the changing of the barrel .can be easily per formed.

' For the same purpose, that is to say for the purpose of a quick and easy barrel changing', the retaining elements for the breech bolt and for the firing pin are arranged in a separate casing, which may be engaged or disengaged by a single movement of the hand.

Finally the closing spring of the breech bolt is built together with the latter so that the Whole breech-mechanism together with the barrel can be removed from the 'Weapon by a single grip of the hand.

. In the accompanyingdrawings one form l of the firearm according to the invention is shown by way of example.

Figure 1 is a sectionalview of the firearm, the barrel of lwhich is in its forward position,

the breech bolt being closed.

Figure 2 shows the weapon in its condition after ring in such position which the barrel and the breech bolt occupy in .consequencg of the recoil-action, the barrel has already struck against the stop, and the breech bolt is engaged by the breech retaining means in its I rearward position.

Figure 3 is a cross sectional view taken on line III-III of Figure 2 from which the coupling of the normally arranged triggerl With the firing mechanism displaced from its normal position by 180 may be seen.

Figure 4 is a top v iew appertaining to Figure 2, partly in section with the sight swung out from the cavity for the magazine.

Figure 5 is a cross sectional view taken on 70 the line V-V of Figure 4.

Figure 6 is a cross sectional view .taken on the line VI--VI of Figure 4.

Figure 7 shows the novel bayonet-j oint for the rear cap. I

Figure 8 shows-a different construction in which the stop is concentrically arranged with respect to the barrel.

Figure 9 shows the rear part of the breech bolt coupled with the barrel, together with 30 the ring pin, the firing-spring, the sleeve for the latter and the closing-spring which are built together with the breech bolt. v

In the casing 1 (Figure 1) the barrel 2 which is subject to the action of the recoilspring .3 is movablyarranged. The rear end of the spring 3 lies in the cap 4: which is secured to the casing 1 by means ofa bayonetjoint. Made inte ral with the barrel 2 or screwed thereon t ere is a barrel extension 50 in which thebreech bolt of the fire-arm moves. In the example Shown in the draw- -ing the breech bolt consists of the well known head portion 5 and the bolt sleeve 6 which cooperate in a known manner by screw thread A against the collar 33 of the sleeve 32. The sleeve 32 is coupled with the bolt sleeve 6 by the aid of its projection 34, (Figures 1 and 9) in such a manner that it may slide therein, this construction enabling the spring 8 to be taken out from the weapon together with the breech bolt. Arranged at the forward end of the bolt sleeve 6 there is a catch 9 in which engages a hook 11 (Figure 4) for retaining the bolt sleeve in its retracted position. The hook 11 is subject to the action ofla sprlng 10, whereby said hook is capable of being swung round the pin 12 (Figures 2 and 4). Pivotally arranged round the pin 12 there are also the'iring hooks 14 and 15 which cooperate with the ring pin 13 and are subject to the pressure of the springs 16and 17 respectively, a corresponding catch 51 being formed on the firing pin 13. The trigger 19 which is subject to the pressure of the spring 18 is pivotally mounted on a pin 20 and is provided with an arm 52 against which the connecting rod 21 is bearing, the latter serving to connect the firing hook 15 with the trigger 19 (Fi ure 3). The firing pin 13 is thus retaine by two hooks 14 and 15 the latter being operated by the trigger 19 and the former by the breech bolt as described in detail in my prior Patent No. 985,156. The operation of the gun is as follows:

When the cartridge in the chamber is fired the barrel 2 and the breech bolt 5, 6 firmly coupled therewith rush backward under the recoil action and thereby press together the springs 3 and 8. The backward slide of the barrel is limited by the stop 23 (Figure 2) which is arranged in the cap 4 and against which the barrel 2 or better said the projection 22 of the barrel extension 50 strikes. The stop is supported advantageously on a powerful spring 24 which allows a slight yielding of the stop but immediately afterwards throws forward the barrel with great force. The stop 23 which constitutes a spring buffer is arranged in such a manner that the projection 22 gets in` touch with the same shortly before the hook 11 has engaged the backward rushing bolt sleeve 6 in its rear position by means of its catch 9. As a consequence of the dash against the spring buffer 23 the barrel 2 is imparted a pulse in the forward direction and in this moment and under the action of the said powerful impulse the loosening of the shell in the chamber which was begun by its inertia is completed and by the further forward rush of the barrel the extraction and ejection of the empty shell is performed.

In Figure 8 v the bu'er is `centrally arranged in the axis of the barrel. In this construction a rearwardly closed cylinder` 53 is used as a stop and is subject to the action of a spring 54. The stop-cylinder is mounted in a cap 55 which just like the cap 4 in the former construction is coupled with the powerful im- A casing 1 by means of a bayonet-joint. The movements of the stop-cylinder are limited by a pin 25 which is mounted in the recess 56 of the cylinder 53. The striking surface of the barrel is formed in this instance by the rear vertical surface 47 of the barrel eX- tension so that a separate abutting projection is superfluous.

Inv order that the gun may be easily and quickly taken apart for the purpose of a barrel change the hooks 11, 14, 15 and the lever 35 for retaining the breech bolt and firing pin in the open position, are arranged 1n a casing 29 which maybe swung around the pin 26 and fixed by means of a bolt 28 sub- 'ect to the action of spring 27 (see Figure 4).

f the bolt 28 is withdrawn and the casing 29 swung round the pin 26 (Figure 1) all the parts of the firearm which may oppose the pulling out of the barrel from the weapon are removed from its path.

In the present firearm it is of utmost importance that the connection of the cap 4 or with the casing 1 should be carried out with absolute security. For this purpose the surfaces of the cap and the casing cooperating with each other at the closing of the bayonet-joint are of a wedge-like shape. There arel arranged on the cap 'couplingwedges 30 (Figures 1, 7 and 8)'-and on the casing 1 corresponding projections 31 for receiving suchwedges or vice versa. For effecting thecouplingthe cap is pushed on the casing in such positihn that the couplingwedges slide by the projections 31. Thereupon the cap is rotated in such a manner that the wedges 30 get in front of the projections 31. If now the cap is released it snaps into its correct place under the action of spring 3. With this mechanism the wedge-like elements 30 and 31 either permit a perfect engagement or they eect a full disengagement under the action of spring 3 (Figure 7). If therefore it is found that the coupling surfaces of this bayonet-joint engage yit is perfectly surec that the coupling has been effected in the right manner.

The taking apart of the gun for the purpose of changing the barrel may be effected in the following manner:

The casing 29 is lifted up and the cap 4 is rotated whereby the said cap together with the spring buffer therein contained and the recoil-spring put into it becomes free. Hereupon the barrel and its extension, the breech bolt, the firing pin, the spring of the liringpin and the closing spring may be pulled out jointly from the weapon. The mounting together of the firearm is effected by the same operations carried out in the reverse order.

I claim:

1. An automatic firearm having abarrel and a breech bolt jointly taking part in the recoil movement, a strikin surface on the .rear end portion of the barre a cap forming the rear termination of the firearm, wedge shaped lugs on the outer side of the casing and on the inner side of the said cap, a spring buffer arranged in the said cap in the path of the said striking surface, the said buffer being adapted to throw forward the barrel at its dashing against the said buffer.

2. An automatic firearm having a barrel and a breech bolt jointly taking part in the recoil movement, means for retaining the breech bolt and means for retaining the firing pin in their4 rear position, the said means being arranged in a casing adapted to be swung out of the path of the barrel, a spring buffer, a striking surface on the rear end portion of the barrel adapted to strike against said spring buffer the latter being adapted to throw forward the barrel at its dashing against the said buffer.

3. An automatic firearm having a barrel and a breech bolt jointly taking part in the recoil movement, a sleeve movably connected with said breech bolt, a spring on the said sleeve, the said spring'being adapted to push the sleeve and thebreech bolt in opposite directions, a spring buffer, a striking surface on the rear end portion of the barrel adapted to strike against said spring buer the latter being adapted to throw forward the barrel at its dashing against the said buffer.

4. An automatic rearm having abarrel and a straight pull breech bolt jointly taking part in the recoil movement, a barrel spring to move the barrel into its foremost position after its recoil movement, means for retaining the breech bolt in its rearmost position, means for releasing the same when the barrel reaches its firing position, a spring to close the breech bolt, a spring buffer, a striking surface on the rear end portion of the barrel adapted to strike against said spring buffer, the latter being adapted to throw the barrel forward upon engagement with said buffer. y 5.v An automatic firearm having a barrel rovided with a barrel extension and a straight pull breechbolt jointly taking part in the recoil movement, a barrel spring to move the barrel into its foremost position after its recoil movement, means for releasing the same when the barrel reaches itsfiring position, a spring to close the breech bolt, a spring buffer, a strikin surface on the rear end of the barrel extension Aadapted to strike against said spring buffer, the latter being Iadapted t'o throw the barrel forward upon engagement with the buffer. l y

6. An automatic .firearm having a barrel provided with a barrel extension, a rear end surface on said barrel extension and a straight pull breech bolt jointly taking part in the recoil movement, a barrel spring to. move .the barrel into its foremost position after lts reco11 movement, means for retain` ing the breech bolt in its rearmost position, means for releasing .the same when the barrel reaches its firing positon, a spring buen in the lpath of the said end surface, the said spring buffer being adaptedl to throw the barrel forward upon engagement with said buHer.

7. An automatic firearm having a barrel and a straight pull breech bolt jointly taking,

part in the recoil movement, a spring to move the barrel into its foremost position after its 4recoil movement, means for retaining the breech bolt in its rearmost position, means for releasing the same when the barrel reaches its firing position, a spring to close l signature.

' RUDOLF v. FROMMER. 

